1. Field of the Invention
This invention relates to electrically conducting materials and to a method of preparing such electrically conducting materials.
2. Description of the Prior Art
Numerous methods for imparting electrical conductivity to synthetic polymeric materials in the form of shaped bodies are known in the art. For example, in U.S. Pat. No. 3,940,533 issued to Arsac, there is proposed one method for imparting electrical conductivity to polymeric shaped materials, such as polyamide fibers, in which the fibers are first contacted with hydrogen sulfide and the resulting fibers impregnated with the hydrogen sulfide are then immersed in a metal salt solution such as an aqueous copper sulfate solution, to form a deposit of metal sulfide, such as copper sulfide, on the fibers. This process, however, is not all together satisfactory in view of the fact that the copper sulfide deposit on the fibers obtained according to this process is poor in stability, especially in washability, so that the electrical conductivity is lost during storage or use. In British patent publication No. 2,078,545 A (published Jan. 13, 1982), there is proposed a method in which an electrically conducting, copper sulfide-coated fiber, obtained a method such as disclosed in the above-mentioned U.S. Pat. No. 3,940,533, is treated with a reducing agent such as ascorbic acid or hydrazine to increase the atomic ratio Cu/S of the copper sulfide to between 1.5 and 2.0. Although the thus treated electrically conducting fiber exhibits superior washability in comparison with the non-treated starting fiber, a further improvement in washability is still desired in practice.